Rock-drill



(NoModl.)

W. R. WILLETTS 8v H. BALL.

ROCK DRILL.

No. 314,897. Patented Mar. 31, 1885.

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UNITED STATES PATENT OEEICE.

WILLIAM I?. WILLETTS AND HARRY BALL, OF STANFORD, CONNECTICUT.

ROCK-DRILL.

SPECIFICATION' forming part of: Letters Patent No., 314,897, dated March 31, 1885.

Appication fied September Q2,

1584. (No model.)

T0 all whom, it may concern:

Be itk nown that we, WILLIAM R. WILLETTs and HARRY BALL, citizens of the United States, residing at Stamford, in the county of Fairfield and State of Connecticut, have invented certain new and useful Improvements in Rock- Drills; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

Our invention relates to that class of rockdrills which are opeiated by steam or compressed air, and has for its objects to so simplify and improve their construction that the friction and consequent wear of the parts will be greatly reduced, and a machine produced which, while economical in cost, shall not be liable to get out of repair, and will perform a greater amount of work and with less power than any machine now in use. Ill/ith these ends in view we have devised the simple and novel construction which we will now describe, referring by letters to the accompanying drawings, forming part of this specification, in which- Figure l is a vertical central section of the cylinder, as on line x m, Fig` 3; Fig. 2, an elevation of the rear cap of the cylinder removed, showing the ratchet-wheel and spring-pawls; Fig. 3, an end elevation of the cylinder, showing the feeding mechanism and port-cap, the plates being indicated in dotted lines, and Fig. 4.- a horizontal central section at a right angle to Fig. 1, as on line y y, Fig. 3.

Similar letters indicate the same parts in all the figures.

A is the' cylinder, having a anged base, A3, and B the piston, the shape of which is clearly shown in Figs. 1 and 4.

B is the piston-rod, and C- the upper cap of the cylinder, which is provided with arecess, C', to accommodate a ratchet-wheel, 0, the function of which will presently be explained.

D is the lower cap, through which the piston-rod passes.

E is a rod having spiral grooves, as shown, which are engaged by corresponding splines in the recess Bfe in the piston, as will be more fully explained.

F is the feed-rod, the yoke or arm which it engages not being shown.

G is the valve which vcovers the ports H and the exhaust H. This valve is operated by a roclslial`t, I. to which it is connected by an arm or rod, I. This rock-shaft is journaled in a socket formed partially in projection a on the cylinder, and partially in plate M, which is securely screwed or bolted to projection A. N is asimilar plate, screwed to projection A', which covers the valve and arm I, forming a small steam-chest, A2, which the steam enters at A4, and then passes to the ports. The rockshaft Iis provided with a cross-piece, L, which is acted on by pins K, which are alternately lifted Vby the inclines Bi upon the piston, the action of said inclines being to tilt or rock shaft I, which causes valve G to pass from one port to the other to control the entrance of steam into the cylinder. It will of course be understood that the drill itself is attached in any suitable manner to the piston-rod B. The rotation of the drill is accomplished by means of the spirally-grooved rod E, which engages the ,pistou This rod is provided with a ratchct-wheel, O, rigidly secured thereto.

O indicates spring-actuated pawls, which engage the ratchet and hold it from turning backward, so that when the piston moves upward-zl c., toward the right iu Fig. l-the piston and piston-rod turn upon the grooves of the spiral rod E; but when the piston moves downward rod E and the ratchet are free to turn, so that the blow of the drill is delivered straight forward. Beyond the ratchet-wheel, rod E passes through a stuiiing-box, P, of any ordinary construction.

Y Q is a gear-wheel, loose upon rod E, which meshes with avgear-wheel, Q', on the feed-rod F, said rod being free to rotate in the base A3 of the cylinder. This gear is preferably tapped on a bushing, Q2, which is secured to the feedrod by a spline or feather, a, so thatwhen gear Q is rotated the feed-rod is carried with it.

It is a beveled friction plate or clutch which slides upon shaft E, and is caused to rotate therewith byaspline upon the shaft engaging a groove. (Not shown.)

R is a knob which is screwed upon the end of shaft E, forcing the bevel of plate R against the loose gear Q, thus locking the gear to the plate and causing it to rotate with shaft E.

The operation is as follows: The power (steam or compressed air, preferably the former) is IOO admitted to the steam-chest A2 through the pipe shown in Fig. 6, and in dotted lines in Fig. 3, and will rush through one of the ports H. (Shown clearly in Fig. l.) Suppose that thesteam has passed into the cylinder through the right-hand port, (the upper one, when in operative positiom) as the piston passes below the middle of the cylinder the right or upper pin, K, begins to travel up the right or upper incline on the piston. This pin,acting on cross-piece L, causes sufficient rotary movement to rock-shaft l to carry valve Gover the upper port, cutting off the entrance of steam into the cylinder above the piston, but allowing it to enter the cylinder at the other port. This raises the piston, the steam in the cylinder above the piston being forced out at the exhaust. The valve continually moves from one port to the other; but the exhaust is continually covered. Vhen the piston is at the upper end of the cylinder, the lower incline on the piston acts on the lower pins to cut off the steam below and to admit it above the piston, these operations being repeated at each stroke ofthe piston. As the piston moves up rod E, having the spiral grooves, is held stationary by the pawls engagingI the ratchetwheel. This causes thepiston to make a partial revolution. As the piston descends it in turn imparts the same amount of rotation to rod E that said rod imparts to the piston during the upward stroke. This movement of rod E carries gear Q with it, provided, of course, that the latter is locked upon the rod. Gear Q meshes with gear Q upon the feedrod, turning said rod, which is screw-threaded its entire length. The mechanism for imparting rotation to the feed-rod is wholly new, and of our invention; but motion is communicated by the feed-rod to the cylinder in the ordinary manner, which we have deemed it wholly unnecessary to illustrate-that is, the feed-rod passes through a correspondinglythreaded opening in a yoke or arm (not shown) projecting from the column U. This acts, of course, to raise or lower the drill, according to the direction in which the feed-rod is rotated. At the upper end of this rod a crank (not shown) is always provided. This crank is used to raise the drill, or for a hand-feed when it is not desired to use the automat-ic feed. As stated above, the automatic feeding mechanism is connected or disconnected by means of knob R', which forces the clutch-plate R into engagement with the loose gear Q, thus locking them together.

To disengage the automatic feed, it is simply necessary to loosen knob R-, which in turn loosens the clutch, thus leaving gear Q loose upon shaft E.

XVe do not desire to limit ourselves to the eXact construction shown, as it is obvious that the details may be varied within reasonable limits without departing from the spirit of our invention.

Having thus described our invention, we claim- W 1. The cylinder and steam-chest having steam and exhaust ports, in combination with a rock-shaft held in place by cap M, and having an arm which carries a valve adapted to slide over said ports, and a cross-piece acted on by pins which are alternately lifted by inclines on the piston, whereby the rock-shaft is vibrated and the valve carried from one port to the other to admit steam alternately above and below the piston.

2. The piston, rod E engaging therewith and having a ratchet and pawls to.hold it against rotation in one direction, in combination with a gear upon the feed-rod, a loose gear upon rod E, and means, as a sliding clutch-plate keyed to said rod, whereby the loose gear and the gear upon the feed-rod may be connected or disconnected, substantially as and for the purpose set forth.

3. The feed-rod, free to rotate in the base of the cylinder and carrying a gear Q, in combination with a recessed piston. a rod, E, having spiral grooves engaging therewith, the ratchet and pawls, a loose gear upon rod E, a sliding clutch-plate held against rotation on said rod, and a knob for forcing the clutchplate into engagement with the loose gear, whereby the automatic feed may be connected or disconnected.

In testimony whereof we affix our signatures in presence of two witnesses.

VILLIAM R. VILLETTS. HARRY BALL.

Witnesses:

GEORGE W. ANDnRsoN, HARRY WILLE'rTs. 

